This disclosure relates to information switching.
Information switching arrangements can route or switch information units (such as packets or other subdivisions such as so-called flits) between multiple inputs and multiple outputs. In such arrangements, arbitration can be needed between information units competing for transmission by the same input or to the same output.
Various approaches have been used for switch arbitration. A general aim is to create or recognise matches for information transmission between inputs and outputs with a view to increasing the number of such matches while still following certain constraints. An example of such a constraint is a limit that one input can perform information transmission to just one output in any individual transmission cycle. There can also be timing constraints for carrying out the arbitration process and making such decisions, and generally speaking a faster switching device will provide less time for carrying out the arbitration process.
Some arrangements rely on input ports or circuits sending multiple requests for information transmission to various output ports or circuits, and receiving one or more grants of access back as a result. Such arrangements can suffer from a loss of efficiency because some of these grants may not be accepted by input circuits which can each only accept one grant at a time.
It is a general aim to improve the efficiency of information switching, for example by improving an arbitration process.